1. Field of the Invention
The present invention relates to a display device. More specifically, the present invention relates to a display device preferably used in a liquid crystal display device, and the like.
2. Description of the Related Art
Currently, various display devices have been used in various applications. A common display device provides color display using a pixel including sub-pixels of three primary colors: red, green, and blue. In such a liquid crystal display device, chromaticity of color displayed in each sub-pixel is adjusted so that the color has a high chroma. As a result, a range of colors which can be displayed (color reproduction range) can be extended. In this case, a transmittance of light which passes through a color filter arranged in each sub-pixel is reduced. Accordingly, use efficiency of light is reduced, and thereby white having an insufficient lightness is displayed.
For this problem, a multi-primary color display device which includes a yellow sub-pixel having a color filter with a high transmittance, in addition to red, green, and blue sub-pixels, is proposed (for example, refer to Japanese Kokai Publication No. 2001-209047). Such a liquid crystal display has a configuration shown in FIG. 36, in which pixels 11w each composed of four sub-pixels 5Rw, 5Gw, 5Bw, and 5Yw which display red, green, blue, and yellow, respectively, and the pixels 11w constitute a display surface 500w. In addition, the following color display device is disclosed. A pixel includes sub-pixels of five colors of red, green, blue, cyan, and yellow, and the sub-pixels are arrayed in the first repeating pattern of red, green, blue, and yellow or in the second repeating pattern of red, green, cyan, and yellow. These liquid crystal devices include a yellow sub-pixel having a color filter with a high transmittance, which suppresses a lightness of white from being reduced. Further, the number of primary colors is increased. As a result, the color reproduction range can be extended.
In a conventional four-primary-color display device, the number of the primary colors used for display is just increased and sufficient display qualities are not obtained. In a display device shown in Japanese Kokai Publication No. 2001-209047, according to a display device having a display surface constituted by pixels each including red, green, blue, and yellow sub-pixels that are the same in aperture area (an area of a region used for display (active region or effective region)), an image with a wide color reproduction range can be displayed, but displayed red is dark. As a result, visibility is deteriorated.
U.S. Patent Application Publication No. 2005/0134785 also disclosed a conventional display device.